JDBCをidea+mavenで実現

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pom.xmlの構成:

        
            junit
            junit
            4.12
            test
        

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class QueryAll {
    public static void main(String[] args){
        Connection conn= null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            //Class.forName("com.mysql.jdbc.Driver");
            String url ="jdbc:mysql://localhost/sunnie?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&useSSL=true";
            String username="root";
            String password="password";
            conn = DriverManager.getConnection(url,username,password);
            stmt = conn.createStatement();
            String sql = "select * from user";
            rs = stmt.executeQuery(sql);
            while(rs.next()) {
                System.out.println("   ：" + rs.getString(2)+"   ："+ rs.getString("password"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (rs!=null)
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            if (stmt!=null)
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            if (conn!=null)
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
        }
    }
}

注意事項:
(1)新しいバージョンのmysqlではserverTimezoneとSSL接続の有無を示す.

serverTimezone=UTC&useSSL=true

警告やエラーが発生します.

java.sql.SQLException: The server timezone value 'UTC' is unrecognized or represents more than one timezone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc timezone value if you want to utilize timezone support.

Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

(2)新しいバージョンmysqlでは、次の行を書く必要がなくなりました.

Class.forName("com.mysql.jdbc.Driver");

書いたらかえって警告が出る

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.